Compatible polyolefin and polyurethane composition



United States Patent Office 3,272,890 COMPATIBLE POLYOLEFIN AND POLY-URETHANE COMPOSITION John M. OLeary, Jr., Wilmington, Del., assignor, by

3,272,890 Patented Sept. 13, 1966 The polyurethane should be present inthe composition in less than a major amount, namely bewteen 5 and 50weight percent, and most preferably between about to about weightpercent, with the remainder being the A 5 polyolefin (minor amounts ofadditives may be present). ii c hij o i l li ti tg i ii h ht 5 33:3233of me Thus, I have discovered that with the compatible polyole Drawing;Ffled Man 4 1963, 252,362 tin-polyurethane compositions of the presentinvention,

4 Claims (1 2 0.4559) where the weight percentage of the polyurethane isbelow about 15 weight percent, it is inadequate to confer satis- Thepresent invention is directed to a compatible poly- 1O factoryresistance properties to attack by hydrocarbon olefin and polyurethanecomposition, and more particularsolvents. Where the concentration of thepolyurethane 1y to a polyolefin and polyurethane blend which may beexceeds about 25 weight percent in the compatible polycompression moldedand flexed, and which is compatible urethane-polyolefin mixture, themixture cannot be molded under ki di i to form containers withoutappreciable difliculty. With- Polyolefins have long had utility forcontainers and 15 in the Weight percentagerange of from 15 to 25 weightother vessels. However, conventional polyolefin containpercent ofpolyurethane, 1t is possible to obtain a transluers have suffered fromthe handicap of possessing a rela- Cent compatlble mlXtllre Yvhlch y beCOmPTeSSIPII i l l rosistanoo t h d b u h as oli e, molded and flexed,and which possesses excellent resistbenzene, kerosene, d th lik It h lproven d ance characteristics to the action of liquid hydrocarbons,sirable to be able to package hydrocarbons in polyole- 2 such asgasoline, benzene, toluene, kerosene, naphtha, etc. fin containers, butdue to this low resistance of the polytemperatufeht whlch the polyolefin15 be heated olefins to hydrocarbons they have suffered as a packagingPflOr t0 the blehdlhg Wlth the Polyurethane 1S p material for thesetypes of liquids. out upon the nature of the polyolefin. The temperatureWhile polyurethanes possess a relatively high degree of hot Precisely Pbut PP ranges y be resistance to liquid hydrocarbons, it has beenthought that 25 glven- Thus, W 1th 10W y p y y namely they ould not besatisfactorily blended with polyolefins. P y y having a denslty of b0-910 and Thus, polyolefins are non-polar materials and require nonp ltemperature range 15 between and polar organic solvents, whilepolyurethanes are polar h hlgh y Polyethylene, namely 3 P 3- tmaterialsand require polar organic solvents. Attempts y h havlng a y above 0-935,lemperature to blend a polyurethane with a polyolefin through the range18 between 255 to whlleowlth P YP blending of solvent mixtures haveproved to be unsatisg the p if rc range isbetween 335 F. to 365 F.

factory because of the antipodal nature of the solvents BY polyolefin asused hereln 1S nt a polyethylene,

and ofthe mixtures or polypropylene, or a polyethylene or polypropyleneThis invention has as an object the provision of a com- 3 3 5 gg g ig lg igg i gg ggiggg y igi fii g g zg g gi l tg polyurethane composltlonand a propylene, or mixtures of a polyethylene or polyproi f acflevlfig6 t h f pylene and one of the aforesaid copolymers. By 1S mven j er Jece PYOVISIOHR a way of example of a copolymer which may be utilizedcorflpatlble polyole n and PO yuret ane f f in the present invention isthe copolymer of ethylene and which possesses excellent resistancecharacteristics in the 40 ethyl acrylate having a major Weightpercentage f poly cold state to hydrocarbon solvents, while at the sameethylene, d hi h i dosignated as D 1 9 The time possessing the stucturalcharacteristics of commercial physical properties of DPD 6169 b i d onoomProspolyolefins. sion-molded plaques unless otherwise indicated) isas Other objects will appear hereinafter. follows:

Property ASTM Test; Method DPD-6169 Melt Index (gms./1O min.) Dl238 52T.6 Density (gins/cc.) Dl50557T 0.931 Vieat Softening Temperature C.)D1525-58T. 64 Hardness D676-I Durometer, Shore A 86 Durometer, Shore D27 Compression Set i After 9 days at 23 (percent re- 56 covery). After22 hrs. at 0. (percent re 18 covery). Tensile Strength (p.s.i 1, 350Elongation 650 Brittleness Index 50% O.K. 105 OK. C.) EnviromnentalStress-Crack Resistance F0 (hours) 500 F50 (1101115) 500 Flex-CrackingResistance at 25 C. (Cycles to Fail) }R0ss Rubber Test Apparatus 2, 000,000 at 0 C. (Cycles to Fail) 2, 000, 000

I have discovered that a polyolefin and polyurethane may besatisfactorily blended to form a compatible composition if thepolyolefin is first melted and brought to a flux in a Banbury mixer, andthe polyurethane added to the molten polyolefin. I have discovered thatif the mixture is subjected to agitation within the Banbury mixer I haveprepared compatible compositions of polyole- 65 fin and polyurethanethroughout the entire weight percentage range of between 5 weightpercent and 50 weight percent of polyurethane, and haveprepared thesemixtures at 5 weight percent intervals within this range. The finalcompositions are compatible throughout this entire for an appreciabletime period, such as on the order 70 of three minutes, the polyurethanewill enter into solution, without the need for solvents.

range, and in its broadest compass the subject invention embracescompositions containing between 5 weight percent and 50 weight percentof polyurethane. However,

as above-indicated, those compositions having between 15 weight percentand 25 weight percent of polyurethane are to be preferred, sincesatisfactory resistance to liquid hydrocarbon solvents cannot beachieved with composiduring the time period of approximately threeminutes, with the polyurethane entering into solution. No solvents ofany kind were added.

The resultant composition in each instance could be tions in which thepolyurethane is below about 15 weight 5 ilexed and compression moldedwithout striation or checkpercent, and satisfactory moldingcharacteristics cannot mg. Thus, the resultant composition in eachinstance be achieved where the polyurethane is present in an constituteda translucent solid.

amount greater than 25 weight percent. h d 1 Example I Due to the highercrystallinity of igh ensity po yy ethylene and polypropylene, it is moredifiicult to prepare 1O Alathon 20 was addedo to a Banburflillxel' andmeltgd compatible polyurethane-polyolefin compositions containat atempefatul'fi of 225 Composltlons betwefiil 6 ing high weightpercentages of polyurethane i hi h Alathon 20 and Estane S74OX2 wereprepared congigting 5 wt. percent 90 wt. percent, 85 wt. percent, wt.density polyethylene or with polypropylene. of 9 As examples ofpolyolefins which h b d i percent, 75 Wt. percent, 70 wt. percent, 65wt. percentE the present invention, may be mentioned the following 15 60percerft, 55 PF and 50 3? materials: DPD-6169; Alathon 10, apolyethylene havg i ggfogg z the remamder each case conslstmg of ing adensity of 0.923 and a melt index of 2.1; Alathon l 14, a polyethylenehaving a density of 0.914 and a melt w each of Phese composltlons a mpindex of 1.8; Alathon 16, a polyethylene having a denlig Was t fs p iffiE i ggj g tg sity of 0.923 and a melt index of 4.0; Alathon 20, a 20Wtpercent 0 W. percen o s ane e polyethylene having a density of 0.921and a melt index 60111130519011 Was both feslstant t0 Organlc Solvfints,511911 of 2.1; Alathon 22, a polyethylene having a densi f as gasollne,kerosene, benzene, toluene, and naphtha, 1n 0.921 and a melt index of3.0; Alathon 34, a polyethylene cold: and was capable of bemgcompresslon molded having a density of 0.930 and a melt index of 3.0;Marlex and flexed- I 3328, a polyethylene having a density of 0.933 anda 25 Example I melt index of 2.8; Marlex 6002, a polyethylene havingEscon 103 was melted in a Banbury mixer and then a density of 0960 and amelt index Marlex 15 wt. percent of Estane 5740X1 was added thereto. apolyethylene having a density of melt index The temperature wasmaintained throughout the meltof 0.9; Marlex 6050, a polyethylene havinga {161181113 of mg and blending at about 0 R The blending was and aIndex of Marlex a PO y ethy1ene 3O effected for three minutes. Theresultant composition havmg density of 5 a melt: Index of Markxpossessed excellent resistance to the action of hydrocara f g' ag i g p%gyg g%i gg Z S i bon solvents and could be compression molded. Addi- H}ex 0 tional compositions were made using the same procedure s ty of 0.95and a melt index 05 4.0; Av gsgg 6 315 with wt. percent and wt. percentof Estane 57 40X1. Polypropylen? having a denslty etween to Thesecompositions likewise possessed superior reslstance a melt 1 1 2 3 5 5:?2 1 fg f to hydrocarbon solvents and could be compression aving 'a me inex a o scon a molded polypropylene having a melt index at 230 C. of 3.5;Example I" and Escon 105, a polypropylene having a melt index at 230 C.of 5.5. 40 Marlex 6002 was melted in a Banbury mixer at 270 Examples ofpolyurethane materials which have been F., and Estane S74OX2 was addedto it at this temperaused in the present invention include Estane5740X1, ture and the mixing continued for a period of three min- EstaneS74OX2 and Estane 5740X7. The properties of utes. Compositions were madeeach consisting of 15 wt. the Estane resins are set forth below:percent, 20 Wt. percent, and 25 wt. percent of the Estane PHYSICALPROPERTIES OF ESTANE RESINS Property Estane Estane Estane ASTM 5740X1S74OX2 5740X7 No.

Specific gravity 1. 20 1'. 20 1. 20 Hardness, Shore:

Scale 88 96 D Scale 35 23 49 Stress-strain properties D-412 Tensilestrength (p 1. 5,840 5,000 5,840

300% Modulus (p.s.i.) 1, 240 420 2, 800

Ultimate elongation (percent) 540 720 490 Abrasion resistance, B. F.Goodrich Pico Abrasion Index I 360 125 110 Taber, C817 wheels, 1,000gm./wheel, 5,000

revolutions (gram loss) 0.0025 0.1515 0.0023

National Bureau of Standards, Method 14111, Federal Test Method Std. 601(percent of standard) Gehman low-temperature, freeze point C.).

Compression set percent at 25 C./22 hours percent at 70 C./22 hours Izodimpat 1:s trength (ft.-lb./in. Notch) 1 Natural rubber abrasion equal to100 on the Pico Index.

In order to illustrate the present invention, there is set forthhereinafter by way of example, and not by way of limitation, thefollowing examples. In each example the polyolefin was first melted in aBanbury mixer, maintained at the temperature indicated in the example,and then polyurethane pellets were added to the molten poly- Example 1VDPD-6169 was melted in a Banbury mixer at 225 olefin. Blending wasachieved in the Banbury mixer F., and Estane 574OX7 was added thereto atthis temperature. Compositions consisting of 5 wt. percent, wt. percent,wt. percent, wt. percent, wt. percent, wt. percent, wt. percent, wt.percent, wt. percent, and wt. percent of Estane 5740X7 were prepared. Ineach instance the composition could be compression molded and flexedwithout striation and checking. The compositions having from 15 to 25wt. percent were tested for resistance to hydrocarbon solvents andcompression moldability and were found to possess superior resistance tohydrocarbon solvents and to be readily compression molded.

Example V A mixture of 50 wt. percent of Alathon 20 and 50 wt. percentof DPD-6l69 were melted in a Banbury mixer at 225 F., and Estane 574OX2were added to the mixture at this temperature. Compositions containing 5wt. percent, 10 wt. percent, 15 wt. percent, 20 wt. percent, 25 Wt.percent, 30 wt. percent, 35 wt. percent, 40 wt. percent, 45 wt. percent,and 50 wt. percent of Estane 574OX2 were prepared. Those having between15 to 25 wt. percent were tested for resistance to hydrocarbon solventsand for compression moldability and were found to possess superiorresistance to hydrocarbon solvents and to be compression moldable. Eachof the compositions throughout the entire range were found to becampatible without striation and checking.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification as indicating the scope of theinvention.

I claim:

1. A molded article formed from a compatible polymer compositionconsisting essentially of a homogeneous mixture of 85 to weight percentof a polyolefin selected from the group consisting of polyethylene,polypropylene, polyethylene copolymer having a major weight percentageof polyethylene, and mixtures thereof, and from 15 to 25 weight percentof polyurethane, which composition possesses excellent resistancecharacteristics in the cold state to hydrocarbon solvents, and may bereadily compression molded.

2. A molded article in accordance with claim 1 in which the polyolefinis polyethylene.

3. A molded article in accordance with claim 1 in which the polyolefinis polypropylene.

4. A molded article in accordance with claim 1 in which the polyolefinis a polyethylene opolymer having a major weight percent ofpolyethylene.

References Cited by the Examiner UNITED STATES PATENTS 2,955,098 10/1960Last 260-859 3,027,343 3/1962 Kane 260-859 3,170,004 2/1965 Farago260859 MURRAY TILLMAN, Primary Examiner.

J. C. BLEUTGE, Assistant Examiner.

1. A METHOD ARTICLE FORMED FROM A COMPATIBLE POLYMER COMPOSITIONCONSISTING ESSENTIALLY OF A HOMOGENEOUS MIXTURE OF 85 TO 75 WEIGHTPERCENT OF A POLYOLEFIN SELECTED FROM THE GROUP CONSISTING OFPOLYETHYLENE, POLYPROPYLENE, POLYETHYLENE COPOLYMER HAVING A MAJORWEIGHT PERCENTAGE OF POLYETHYLENE, AND MIXTURES THEREOF, AND FROM 15 TO25 WEIGHT PERCENT OF POLYURETHANE, WHICH COMPOSITION POSSESSES EXCELLENTRESISTANCE CHARACTERISTICS IN THE COLD STATE OF HYDROCARBON SOLVENTS,AND MAY BE READILY COMPRESSION MOLDED.